Re: optimization/8300: [3.2/3.3/3.4 regression] [sparc] ICE in gen_reg_rtx, at emit-rtl.c:662

[Robert Schiele <rschiele at uni-mannheim dot de>]

The following reply was made to PR optimization/8300; it has been noted by GNATS.

From: Robert Schiele <rschiele at uni-mannheim dot de>
To: Richard Henderson <rth at redhat dot com>, rth at gcc dot gnu dot org, gcc-bugs at gcc dot gnu dot org,
   gcc-prs at gcc dot gnu dot org, nobody at gcc dot gnu dot org,
   tneumann at pi3 dot informatik dot uni-mannheim dot de, gcc-gnats at gcc dot gnu dot org
Cc:  
Subject: Re: optimization/8300: [3.2/3.3/3.4 regression] [sparc] ICE in gen_reg_rtx, at emit-rtl.c:662
Date: Mon, 17 Mar 2003 10:25:04 +0100

 --AqsLC8rIMeq19msA
 Content-Type: text/plain; charset=us-ascii
 Content-Disposition: inline
 Content-Transfer-Encoding: quoted-printable
 
 On Mon, Mar 17, 2003 at 01:05:55AM -0800, Richard Henderson wrote:
 > On Mon, Mar 17, 2003 at 06:08:21AM +0100, Robert Schiele wrote:
 > > *(&c + 1) is also well defined.
 >=20
 > How's that?
 
 It's pointer arithmetic:
 
 Assume you have the following memory layout...
 
 |   |
 +---+
 |   | <=3D=3D ... then the contents of that address is *(&c + 1)
 +---+
 | c |
 +---+
 |   |
 
 It is:
 
 c: The contents of the variable c on the stack.
 
 &c: The address where c is located on the stack.
 
 &c + 1: That address plus 4 byte. (sizeof(int) =3D=3D 4 on sparc)
 
 *(&c + 1): The contents of the above address.
 
 > > 1. My rewritten example is legal code with no doubt and produces an
 > >    ICE whit optimization.
 >=20
 > Nyet.
 
 Well, I still don't see why this is illegal. Can you give me the
 paragraph of the C standard that prohibits this sort of pointer
 arithmetic?
 
 Robert
 
 --=20
 Robert Schiele			Tel.: +49-621-181-2517
 Dipl.-Wirtsch.informatiker	mailto:rschiele at uni-mannheim dot de
 
 --AqsLC8rIMeq19msA
 Content-Type: application/pgp-signature
 Content-Disposition: inline
 
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.0.7 (GNU/Linux)
 
 iQEVAwUBPnWUcMQAnns5HcHpAQGdKggAlK9ZV4OgrAY+7UCvuoO7BbUg6PgbHhXQ
 02LxCX3fN5FXsyvj5nVfD8ZbwK42rh6w95hb0XloKZwQMM7+izJala5SEOgghyUN
 l3Wlr7f30yJOudPHFanqBtyfOuQJP9gWBfFIssIDtdAOx+ZpBxb8XGbpex5EAPWG
 T5/DBchE6zrM46R7XCBdRurZ2PFTh6E9k7dJwfjOh+h5O0R6Npvv3NLHuvdfHfJk
 vCfyZgRM8K96KmOzmetAytCsU01aD/6UsGOPhntnlqpOfysC87aPAJ9Zam6wCmMr
 pq8hzQa7hdaVVUjnZbltLMQ/XY1/mHft6S1C95eekY5EPtFVEzCO1w==
 =0Vp8
 -----END PGP SIGNATURE-----
 
 --AqsLC8rIMeq19msA--